By Andreas Kluth ( Andreas Kluth is a columnist for Bloomberg Opinion)
For the past year, an assumption — sometimes explicit, often tacit — has informed almost all our thinking about the pandemic: At some point, it will be over, and then we’ll go “back to normal.”
This premise is almost certainly wrong. SARS-CoV-2, protean and elusive as it is, may become our permanent enemy, like the flu but worse. And even if it peters out eventually, our lives and routines will by then have changed irreversibly. Going “back” won’t be an option; the only way is forward. But to what exactly?
Most epidemics disappear once populations achieve herd immunity and the pathogen has too few vulnerable bodies available as hosts for its self-propagation. This herd protection comes about through the combination of natural immunity in people who’ve recovered from infection and vaccination of the remaining population.
In the case of SARS-CoV-2, however, recent developments suggest that we may never achieve herd immunity. Even the U.S., which leads most other countries in vaccinations and already had large outbreaks, won’t get there. That’s the upshot of an analysis by Christopher Murray at the University of Washington and Peter Piot at the London School of Hygiene and Tropical Medicine.
The main reason is the ongoing emergence of new variants that behave almost like new viruses. A clinical vaccine trial in South Africa showed that people in the placebo group who had previously been infected with one strain had no immunity against its mutated descendant and became reinfected. There are similar reports from parts of Brazil that had massive outbreaks and subsequently suffered renewed epidemics.
That leaves only vaccination as a path toward lasting herd immunity. And admittedly, some of the shots available today are still somewhat effective against some of the new variants. But over time they will become powerless against the coming mutations.
Of course, vaccine makers are already feverishly working on making new jabs. In particular, inoculations based on the revolutionary mRNA technology I’ve previously described can be updated faster than any vaccine in history. But the serum still needs to be made, shipped, distributed and jabbed.
And that process can’t happen fast enough, nor cover the planet widely enough. Yes, some of us may win a regional round or two against the virus, by vaccinating one particular population — as Israel has done, for instance. But evolution doesn’t care where it does its work, and the virus replicates wherever it finds warm and unvaccinated bodies with cells that let it reproduce its RNA. As it copies itself, it makes occasional coding mistakes. And some of those chance errors turn into yet more mutations.
Consider two alternative evolutionary paths. In one, a virus becomes more severe but not more transmissible. It will cause more disease and death, but the growth is linear. In the other path, a mutating virus becomes neither more nor less virulent but more contagious. It will cause increases in disease and death that are exponential rather than linear. Adam Kucharski at the London School of Hygiene and Tropical Medicine explains the math here.
If this is the evolutionary trajectory of SARS-CoV-2, we’re in for seemingly endless cycles of outbreaks and remissions, social restrictions and relaxations, lockdowns and reopenings. At least in rich countries, we will probably get vaccinated a couple of times a year, against the latest variant in circulation, but never fast or comprehensively enough to achieve herd immunity.
I’m not arguing for defeatism here. In the grand sweep of history, Covid-19 is still a relatively mild pandemic. Smallpox killed nine out of 10 Native Americans after the Spanish brought it to the Americas in the 16th century. The Black Death carried off about half of the Mediterranean population when it first came to Europe in the sixth century. Worldwide, the coronavirus has killed fewer than four in 10,000 so far. And with our science and technology, we’re armed as our ancestors never were.